Article Addendum PHYSARUM ATTRACTION: WHY SLIME MOULD BEHAVES AS CATS DO?
Article addendum PHYSARUM ATTRACTION: WHY SLIME MOULD BEHAVES AS CATS DO? Andrew Adamatzky* and Ben De Lacy Costello University of the West of England, Bristol, BS16 1QY, United Kingdom Keywords: Physarum polycephalum, chemical attraction, pheromones A plasmodium, the vegetative phase of the acellular slime mould Physarum polycephalum, has recently became a popular biological substrate for making experimental laboratory prototypes of living computing devices1. The Physarum-based computing devices are programmed using gradients fields generated by discrete configurations of chemo-attractants. Laboratory experiments shown that the plasmodium of P. polycephalum is attracted to glucose, maltose, mannose, galactose, many aminoacids (e.g. phenylalanine, leucine, serine, asparagine, theonine). Recently we found, see paper2, that the plasmodium is strongly attracted to herbal calming/somnipherous tablets Nytol3 and Kalms Sleep4. To select the principle chemo-attractant in the tablets we undertook laboratory experiments on the plasmodium's binary choice between samples of dried herbs/roots: Valeriana officinalis, Humulus lupulus, Passiflora incarnate, Lactuca virosa, Gentiana lutea, Verbena officinalis (Fig. 1). We constructed a hierarchy of chemo-attractive force (Fig. 2) and found that Valerian root was the strongest chemo-attractant for P. polycephalum2. A possible link between sedative activity of valerian and its chemo-attraction --- via relaxation of contractile activities --- is outlined in2. Valerian contains hundreds of identified, and possibly the same amount of not yet identified, components including alkaloids, volatile oils, valerinol, and actinidine (Fig. 3a)5-8. We can postulate that slime mould in the plasmodium stage may be attracted to a plant because the plant roots or stem harbour high level of food (bacteria), or the plant may provide protection for the slime mould from insect predators (e.g.
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